POSIX Thread Implementation of Sleeping Barbers Problem

whouton (1)
Hi all,

I'm working on simulating the sleeping barber anecdote. I believe my code is sound, but when I run it, it produces strange output. I have included the code below and sample output. I'm just not sure why the output appears to be operating serially and allowing only 2 customers to enter the barber shop at a time regardless of the number of available waiting seats. I suspect I'm using the semaphores incorrectly but can't seem to puzzle out how. If someone could point me in the right direction, I would much appreciate it. 

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sem_t customerReady;
sem_t barberReady;
sem_t accessWRSeats;
unsigned int numberOfAvailableSeats = 0;
unsigned int numberOfCustomers = 0;

int HOURS = 1;
int amountTime = 0;

void *barber(void*){
    while(amountTime < HOURS*60){
   	 sem_wait(&customerReady);//Check to see if there are any customers ready and if not, sleep
   	 sem_wait(&accessWRSeats); //Wake up and and try to access the # of available seats and if not, sleep
   	 //Enter Critical Section
	 //If there are any customers in the waiting room
	 //If there aren't any customers in the waiting room
	
	cout << "\nBarber: number of customers: " << numberOfCustomers;
	
		numberOfCustomers--;
		numberOfAvailableSeats++;//Take a customer from the wait room to the barber chair
	//Cut hair here
   	 sem_post(&accessWRSeats);//Release lock on available seats; chairs are unlocked
	sem_post(&barberReady);//Finish cutting hair and is ready to cut again
	 amountTime++;
    }
	cout << "EXITING BARBER!" << endl;
    pthread_exit(NULL);    
}

void *customer(void *){
    while(amountTime < HOURS* 60){
   	 sem_wait(&accessWRSeats); //Request access to the number of available seats in the waiting room
  	   	 //If there are seats available, do not leave (wait)
   	 if(numberOfAvailableSeats > 0){
		numberOfCustomers++;//customer enters the barber shop
		cout << "\n\tCustomer: number of Customers: " << numberOfCustomers;

   		numberOfAvailableSeats--;//Sit down in a chair
		 
   		 sem_post(&customerReady);//Signal that there is a customer ready to be served
   		 sem_post(&accessWRSeats);//release lock on seats; lock not needed
   		 sem_wait(&barberReady);//Wait until the barber is ready
   	 }
	 //no free seats
	 else{
	     cout << "\nCustomer:no fucking seats , number of available seats is:" << numberOfAvailableSeats << endl;
		 	cout << "\n\tNumber of available seats:" << numberOfAvailableSeats;
			cout << "\tNumber of Customers:%d\n" << numberOfCustomers << endl;
		 sem_post(&accessWRSeats); //release the lock on the seats and leave without a haircut
	 }
	 amountTime++;
    }
    cout << "EXITING CUSTOMER!" << endl;

	pthread_exit(NULL);
}

int main(int argc, char** argv){   
    //get the number of seats available from the command line
    if(argc == 2){
	 numberOfAvailableSeats = atoi(argv[1]);    
    }
    else {
   	 cout << "Please enter the number of seats you would like to simulate." << endl;
   	 cin >> numberOfAvailableSeats;
    }
	
	/*Semaphore initialization*/
	sem_init(&barberReady,0,1);
	sem_init(&customerReady,0,0);
	sem_init(&accessWRSeats,0,1);
    
    pthread_t barberThread;
    pthread_t customerThread;
    int rc1 = 0; int rc2 = 0;
    rc1 = pthread_create(&barberThread, NULL, barber, NULL);
    rc2 = pthread_create(&customerThread, NULL, customer, NULL);
	
	if(rc1 != 0)
		cout << "Unable to create barber thread." << endl;
	if(rc2 != 0)	
		cout << "Unable to create customer thread." << endl;
			
	/*Customer_thread first blocked*/
	rc2 = pthread_join(customerThread,NULL);
	rc1 = pthread_join(barberThread,NULL);	
	
	printf("rc1: %d, rc2: %d\n", rc1, rc2);
	cout << "EXITING PROGRAM" << endl;
	return 0;
}



./Barber
Please enter the number of seats you would like to simulate.
27

	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1
	Customer: number of Customers: 1
	Customer: number of Customers: 2
Barber: number of customers: 2
Barber: number of customers: 1EXITING CUSTOMER!
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